Research On Regenerative Braking And Stability Control Strategy Of Distributed Drive Electric Vehicle

Due to its advantages in energy conservation and emission reduction,electric vehicles are considered to be the best way to solve the current social energy and environmental crisis.As the unique function and key technology of electric vehicles,regenerative braking control technology plays an important role in automobile energy conservation and environmental protection.The distributed drive electric vehicle can realize precise four-wheel independent control,which is beneficial to improve the braking stability and energy recovery efficiency of the automobile.In recent years,it has become a research hotspot.In this paper,the distributed drive electric vehicle is taken as the research object.The application range of regenerative braking and the structural advantages of distributed drive are fully considered.Based on the theory of fuzzy control,sliding mode control and control distribution,the regeneration of straight and turning brakes is mainly studied to improve the stability performance and energy saving potential under general braking conditions.Firstly,the structure of regenerative braking system is analyzed.Based on this,the overall scheme of regenerative braking control is put forward.When driving in straight line,the main objective is to stabilize the braking direction and take into account the energy recovery.When turning,the goal is to improve the stability performance and energy efficiency optimization.The dynamic model and subsystem models of distributed drive electric vehicle are established by MATLAB/Simulink and CarSim software,and the model is validated.Then,using the fuzzy control theory,the regenerative braking and stability control strategy under general linear conditions is proposed.For the front and rear axle braking force distribution,based on the ECE regulations,the ideal braking force distribution curve and the characteristics of the electromechanical composite braking system,considering the road surface conditions,the front and rear axle braking force distribution coefficients are optimized,and the distribution is determined according to the braking strength.Aiming at the electromechanical braking force distribution of each wheel,a fuzzy controller with brake strength and battery state of charge as input and motorbraking participation ratio as output is designed to coordinate the electromechanical composite braking.This strategy can make full use of the road surface adhesion conditions to maximize energy recovery while ensuring stable braking.The regenerative braking and stability control strategy under general turning conditions is proposed by using hierarchical control theory.The economic objective of optimum energy consumption efficiency and the stability objective of minimum yaw moment tracking error are established respectively.The control effects of different targets are compared.Based on this,a dynamic adjustment method with energy saving and stability is proposed.The upper layer calculates the direct yaw moment for maintaining the stability of the vehicle based on the sliding mode control theory,and the lower layer uses the quadratic programming theory for torque distribution.This strategy improves the handling stability and energy efficiency of the vehicle.Finally,the dSPACE hardware-in-the-loop test platform is built to verify the effectiveness of the control strategy.